Those are the raw values stored by the Attribute Value. I suspect you are using the "RawValue" option when using the "Attribute" lava filter. You shouldn't not use that option if you want the nicely formatted attribute value. If you don't use "RawValue", in your Lava, Rock will output the formatted value based on the specific field type.
This page shows how attribute values are stored in the database based on their field type. When you use "RawValue" in Lava, it's these values that you will see.